residual cancer burden calculator

What is Residual Cancer Burden?

Residual Cancer Burden (RCB) is a standardized way to quantify how much invasive cancer remains after neoadjuvant therapy, usually in breast cancer care. Instead of a simple yes/no response, RCB gives a continuous score (RCB index) and a category (RCB-0, RCB-I, RCB-II, RCB-III) that can be used alongside stage, subtype, and other pathology findings.

Why this calculator matters

After preoperative treatment, pathology reports can include several measurements that are difficult to combine mentally. This calculator quickly organizes key values and estimates an RCB index in a consistent way.

• Useful for educational review of pathology data
• Supports multidisciplinary discussion
• Helps communicate residual disease burden in a structured format

Inputs used in the calculation

1) Residual tumor bed dimensions

Two largest dimensions (in millimeters) are used to estimate residual tumor bed area.

2) Overall cancer cellularity

This represents how much of the residual tumor bed contains carcinoma (as a percentage).

3) In situ percentage

The fraction of carcinoma that is non-invasive (in situ). The calculator adjusts invasive burden based on this value.

4) Positive node count and largest nodal metastasis

The nodal component incorporates both number of involved lymph nodes and size of the largest nodal metastasis.

How to interpret RCB class

• RCB-0: Pathologic complete response (no residual invasive disease in breast and nodes).
• RCB-I: Minimal residual disease (low burden).
• RCB-II: Moderate residual disease.
• RCB-III: Extensive residual disease.

Common cut points used here: RCB-I ≤ 1.36, RCB-II > 1.36 to ≤ 3.28, RCB-III > 3.28.

Important limitations

This page provides a practical implementation for quick estimation. Clinical treatment decisions should always be based on full pathology review, institutional reporting standards, molecular subtype, imaging, and oncologist judgment.

• Measurement technique variability can affect results.
• Pathology sampling and interpretation differences may exist.
• This estimate should not be used in isolation for prognosis or treatment changes.

Quick workflow tip

If you're entering values from a report, copy them exactly as documented and keep units in millimeters. Small unit mistakes (cm vs mm) can dramatically alter the calculated score.